1. Field of the Invention
This invention relates to anti-static film- and fiber-forming synthetic polymers.
2. Description of the Prior Art
The production of films, filaments, and fibers of linear synthetic polymers has long been known. One deficiency of hydrophobic synthetic polymers has been their resulting tendency to build up a static charge. When such filaments or fibers are utilized in the construction of fabrics or in the construction of carpeting, this deficiency is especially disadvantageous. Polyoxyalkylene polymers have been incorporated with film- and fiber-forming synthetic polymers prior to extrusion of the polymers into films and fibers in order to reduce the tendency of such films and fibers to develop a static charge. Such compositions have not proved entirely satisfactory since some of these compositions attract and retain soil more than the unmodified hydrophobic synthetic polymers. In addition, such modified hydrophobic synthetic polymers are more difficult to clean as a result of the presence of the polyoxyalkylene polymer.
In British Pat. No. 1,541,942 there is disclosed a process for the preparation of hydrophobic polyester films and fibers by a process wherein from 5 to 50% by weight, based upon the total weight of the mixture, of a water-soluble sulfonate group-containing polyester are added to a fiber-forming polyester, prior to the spinning operation. Subsequent to extrusion, the water-soluble sulfonate group-containing polyester is washed out of the fiber to leave voids in the fiber and thus produce polyester filaments and fibers having greater water retention capacity so that the tendency toward acquiring and retaining an electrostatic charge is reduced.
Branched water-dispersible polyesters are disclosed in U.S. Pat. No. 4,156,073 as prepared by reacting a polycarboxylic acid, a diol, and an aromatic carboxylic acid containing a --SO.sub.4 M grouping which is attached to the aromatic nucleus of said carboxylic acid through an aliphatic chain and ester linkge. It is further disclosed in U.S. Pat. No. 4,145,469, and references cited therein, that sulfonate or phosphate group-containing polyesters can be treated with an aqueous solution of a polyvalent metal ion reactive with said sulfonate or phosphate groups in said polyester in order to prepare a water-insoluble polyester product.